ERDM-201 - "It's been years since we've been together..." 70's and 60's I had sex with my wife's mother... 4 hours of immoral and naughty relationship

My wife was hospitalized due to childbirth, so my elderly mother-in-law came to Tokyo from the countryside. My wife and I met late, but thankfully we were given the opportunity, and my mother-in-law seems to be happy as well. However, I have a secret that I can't tell my wife... It means that he has sexual feelings towards his mother-in-law rather than his wife. For a while, something happens in the house where I am alone with my mother-in-law...